Portable electronic devices are important tools in many industries. Miniaturization and ruggedization permit employment of portable units in diverse, sometimes hostile environments. Many such devices employ keypads or other components such as touch-sensitive panels to permit entry of data by the user. Under conditions of heavy use the keys and bezel of the keypad may become worn, exposing the unit to potential damage. On occasion the keypad may become partially or completely unresponsive to touch. Replacement of a such a keypad currently requires factory overhaul, resulting in considerable expense and down-time.
A touch sensitive panel is typically mounted above a liquid crystal display panel which presents a range of selections to the user; depressing the surface of the touch sensitive panel communicates the selection to the device. In other applications the touch panel accepts the signature of a customer to denote, for example, receipt of a parcel. Under conditions of heavy use the surface of the touch sensitive panel may become cloudy, marred or torn, obscuring the image below and exposing the unit to potential damage. On occasion the circuitry of the touch sensitive panel may become partially or completely unresponsive to touch. Replacement of such a panel currently requires factory overhaul, resulting in considerable expense and down-time.
Since the unit as a whole must perform satisfactorily under wide temperature ranges and be highly resistant to intrusion by water, dust and other environmental hazards, user-replaceable device components such as the keypad or touch screen panel represents a significant engineering challenge.